Tags: patch

Hi,

I'm hoping this can serve as a unified "omnibug" for all the overlapping
discourse scattered about regarding buffer-display options and the
behavior they produce. The main focus will be those aspects impacting
ERC 5.6 and how they integrate with the upstream display-buffer facility
provided by window.el. In a sense, this is a spiritual successor to

  bug#51753: ERC switches to channel buffer on reconnect

and will inherit the outstanding display-related portions of

  bug#60428: 30.0.50; ERC >5.5: Make M-x erc a more welcoming entry point

the most recent being this proposal:

> This bug's original patch set tried to walk back an austere aspect of
> bug#51753's changes that lumped interactive buffer creation in with
> protocol driven creation. It mainly did so by introducing a new option,
> `erc-interactive-display', that reinstated direct window-buffer
> replacement when running M-x erc. However, as pointed out by Corwin on
> Libera, this did not account for interactive /JOINs.
>
> The attached patch aims to address this oversight as well as simplify
> the display-options picture a bit further by consolidating the roles of
> `erc-interactive-display' and `erc-query-display'. The thinking is that
> both options cover the same basic ground involving buffers created as a
> consequence of issuing slash commands. This patch also adds an interface
> for other such commands to use for detecting when they're being called
> from the command line.

Despite this, I'm still rather unsure about merging our ancient display
options. Aliasing `erc-interactive-display' to `erc-query-display' seems
sane because the latter only appears once, in an interactive command. A
more daring and arguably more meaningful move would be to repurpose
`erc-auto-query' (newly aliased to `erc-receive-query-display') as
something like a more general `erc-receive-display', which could cover
display handling for anything protocol driven (i.e., "non-interactive").
Among the reasons to abstain might be

  1. it would necessarily involve redefining the meaning of the option's
     nil value to mean "fall back to erc-join-buffer" instead of "print
     to the server buffer instead," which has no available alternative

  2. it invites an initial security risk (reminiscent of bug#51753)
     or at least a service interruption

For the first point, redefining the nil value is probably justified in
theory because all other values only concern themselves with where a
buffer is displayed, not where messages are routed for printing or
whether buffers are even created, which is the province of dedicated
switches (see note below re `erc-query-on-unjoined-chan-privmsg'). So I
guess this really comes down to whether providing an alternative
companion option and noting it in the doc string is an acceptable trade
off. Point two is more challenging but could perhaps be addressed by a
one-off warning requiring a click-through, before which
`erc-join-buffer' (now `erc-buffer-display') would remain in effect.

There's also the matter of assigning Custom groups for these options.
It'd be "nice" if we could tag these with multiple groups rather than
confine them to exclusive ownership. They're currently spread over
`erc-buffers', `erc-query', and `erc-display'. All seem to have valid
claims when you consider their respective constituencies.

It's also been casually suggested that we might consider deferring to
`erc-setup-buffer' in areas not directly involved in message handling,
such as in erc-sidebar, to allow the options in question to influence
how buffers are displayed more generally. Not sure I have an opinion on
this quite yet, but if anyone else does, please share.

Lastly, I've tacked on another patch that's somewhat related in the
buffer-creation (but not so much -display) sense. It concerns the
restoration of the option `erc-query-on-unjoined-chan-privmsg', which
was orphaned in 5.5 (by me) both out of ignorance and an abundance of
caution.

Thanks.


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